Cellular phones connect to a cellular mobile network via cell towers. Each cell tower may correspond to a particular coverage area. When a user of a cell phone moves from a first coverage area to a second coverage area, the cell phone needs to seamlessly associate with a cell tower of the second coverage area in order for a phone call not to be dropped. To do so, all of the cell towers associated with the user's cellular service need to operate in the same clock domain. Cell towers operate in the same clock domain when they are synchronized based on a similar frequency (e.g., the cell towers operate at frequencies that are within +/−50 parts per billion (PPB) of each other).
Traditionally, telecommunication networks included time-division multiplexing (TDM) networks that relied on Synchronous Optical Networking and Synchronous Digital Hierarchy (SONET/SDH) technology to carry synchronization information. Currently, cellular mobile networks include next generation networks (NGNs) (e.g., Long Term Evolution (LTE) networks, 3G networks, 4G networks, etc) that utilize a Synchronized Ethernet (SyncE) network to exchange information. Since synchronization (timing/frequency) information is exchanged in a SyncE network via physical timing signals, not packets, the timing signals need to be handled on each hop (e.g., by each router).
A SyncE network may include multiple routers. Each router may include multiple line cards. A router, of a SyncE network, may handle a timing signal by determining that the timing signal is qualified before transmitting the timing signal (information of the timing signal) to a different router. Yet, currently, only a single line card of a router determines that an incoming timing signal is qualified before passing the signal through the other line cards of the router, which do not qualify the signal again, to a different router. Software and/or hardware issues at one of the other line cards may disrupt the signal and cause a change in the frequency. As a result, signals with substantially different frequencies (e.g., frequencies that are not within +/−50 PPB of each other) may be delivered to different cell towers. Consequently, cell phone calls may be dropped when a cell phone moves from a first coverage area to a second coverage area, which is associated with a cell tower that uses a frequency substantially different from the one used by a cell tower associated with the first coverage area.